servo: Merge #16269 - Add an Atom::from_addrefed function (from heycam:atom-already-addrefed); r=upsuper

Source-Repo: https://github.com/servo/servo
Source-Revision: a55cb8425dc41fc6909047841c985a4ede3fa8f9

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 3c10fda187ecc29117d9f10c6d1469a4ceca3522

servo/components/style/gecko/wrapper.rs

@@ -694,7 +694,7 @@ impl<'le> PresentationalHintsSynthetizer for GeckoElement<'le> {
             let global_style_data = &*GLOBAL_STYLE_DATA;
 
             let pdb = PropertyDeclarationBlock::with_one(
-                PropertyDeclaration::XLang(SpecifiedLang(Atom::from(ptr))),
+                PropertyDeclaration::XLang(SpecifiedLang(unsafe { Atom::from_addrefed(ptr) })),
                 Importance::Normal
             );
             let arc = Arc::new(global_style_data.shared_lock.wrap(pdb));

servo/components/style/gecko_string_cache/mod.rs

@@ -197,6 +197,16 @@ impl Atom {
                       "Called from_static for a non-static atom!");
         atom
     }
+
+    /// Creates an atom from a dynamic atom pointer that has already had AddRef
+    /// called on it.
+    #[inline]
+    pub unsafe fn from_addrefed(ptr: *mut nsIAtom) -> Self {
+        debug_assert!(!ptr.is_null());
+        unsafe {
+            Atom(WeakAtom::new(ptr))
+        }
+    }
 }
 
 impl Hash for Atom {